1. Field of the Invention
The present invention relates to an insertion apparatus including an inserting section extended along a longitudinal axis, and a rotary unit which is rotatable in directions around the longitudinal axis with respect to the inserting section.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 2008-93029 discloses an endoscope apparatus which is an insertion apparatus including an inserting section extended along a longitudinal axis, and a rotary unit which is rotatable in directions around the longitudinal axis with respect to the inserting section. The rotary unit includes a spiral fin portion spirally extended around the longitudinal axis. The spiral fin portion is placed toward a first periaxial direction side which is one of directions around the longitudinal axis as the spiral fin portion extends from a proximal direction toward a distal direction. In a lumen, when the rotary unit is rotated in the first periaxial direction in a state that the spiral fin portion is in contact with a luminal paries, a first propulsive force toward the distal direction acts on the inserting section and the rotary unit. On the other hand, when the rotary unit is rotated toward a second periaxial direction opposite to the first periaxial direction in the state that the spiral fin portion is in contact with the luminal paries, a second propulsive force toward the proximal direction acts on the inserting section and the rotary unit. Mobility of the inserting section in directions parallel to the longitudinal axis in the lumen can be improved by the first propulsive force and the second propulsive force.
Further, in this endoscope apparatus, a speed change operation button configured to input a speed change operation for changing a level of a rotating speed of the rotary unit is provided. With the speed change operation, a drive state of a motor as a drive member configured to generate a drive force of rotating the rotary unit is changed. When the speed change operation button is pressed, a magnitude of the rotating speed of the rotary unit is reduced by half as compared with a case where the speed change operation button is not pressed. Therefore, when the speed change operation button is pressed, rotation amounts of the rotary unit in the first periaxial direction and the second periaxial direction are reduced during a reference time having a predetermined length. When a magnitude of a first rotation amount of the rotary unit in the first periaxial direction during the reference time varies, an acting state of the first propulsive force changes, and a first moving amount of the inserting section toward the distal direction during the reference time changes. That is, when the first rotation amount of the rotary unit toward the first periaxial direction during the reference time is reduced, the first moving amount of the inserting section in the distal direction during the reference time is decreased. Likewise, when a magnitude of the second rotation amount of the rotary unit in the second periaxial direction during the reference time varies, an acting state of the second propulsive force changes, and a second moving amount of the inserting section toward the proximal direction during the reference time changes. That is, when the second rotation amount of the rotary unit toward the second periaxial direction during the reference time is reduced, the second moving amount of the inserting section in the proximal end direction during the reference time is decreased.